Laser guarded industrial press safety system

ABSTRACT

A safety system for an industrial press having a moveable section ( 30 ), the safety means including: a laser emitting means ( 1 ) for emitting a continuous planar laser beam ( 9 ) having a generally constant lateral width; a light receiving means ( 22 ) for receiving the laser beam and for detecting when an object intersects the laser beam; and a control means for stopping or preventing movement of the moveable section of the press when the receiving means detects that the laser beam has intersected an object.

The present invention is generally directed to safety systems used inindustrial applications, and in particular to safety systems for use onindustrial presses such as a press brake or guillotine,

The dangers associated with the operation of industrial presses hasnecessitated the development of various safety arrangements to protectworkers using such presses. Safety light curtain systems are commonlyused to provide a plurality of parallel infrared (IR) light beams as a“barrier” for the press. The breaking of any of the IR light beams bythe operator of the press results in the stopping of the operation ofthe press. Those safety light curtains must however be located asignificant distance in front of the press to operate with anyeffectiveness. This is because of the degree of dispersion of the IRlight beams over the extended distances limits the accuracy and speed ofoperation of such light curtains.

In British Patent No. 1307078, there is described a light curtain guardfor a press brake of the kind having an upward stroking ram, commonlyknown as an upstroking press brake. The light curtain guard is alsoformed by a series of parallel light beams, the main difference beingthat the light curtain guard is supported an and moveable with theupward stroking ram. It should be noted that both upstroking pressbrakes and downstroking press brakes having a downward stroking ram arewell known in the market.

Cynum industrie S.A. have since around 1981 been marketing a press brakehaving a safety apparatus including a laser emitter and receiver mountedon opposing sides of the bottom anvil of the press brake and emittingsingle laser beam close to the surface of the anvil. In an upstrokingmachine, the laser emitter and receiver move together with the anvil.

In Australian Patent No. 667057, there is described a safety apparatusfor use on a downstroking press brake having a moving upper blade andstationary anvil. The safety apparatus differs from the Cynum pressbrake in being mounted on the upper blade rather than on the anvil, thesafety apparatus otherwise operating in the same manner by emitting atleast one beam of light in close relation to the leading edge of theupper blade. The light beam can be either an IR or a laser beam.

Fiessler Electronik are marketing a press brake safety apparatus similarto the apparatus described in the abovenoted Australian Patent, butincludes additional parallel laser beams for providing a larger safetyzone adjacent the upper blade of the press brake.

In all of the above-described systems the breaking of the one or morelight beams causes the press brake to stop or prevents the press brakefrom operating. Furthermore, the safety apparatus in all of the abovepress brakes are mounted on and movable with the moving part of thepress brake, whether it is the upper blade or the bottom anvil.

The above noted Systems however have certain disadvantages. Firstlybecause all of the above arrangements rely on one or a series ofparallel IR or laser beams to provide a barrier, there is always thepossibility of the safety light curtain being inadvertently bypassed byan object passing the light beam or passing between adjacent parallellight beams and not breaking any of the light beams. The single lightbeam or safety light curtain is therefore ineffectual under thesecircumstances.

Also, in the case of arrangements using laser beams, vibrations canseriously distort the path of the laser beam causing disruptions andinaccuracies in the operation of such arrangements. Although the use ofsoftware “filtering” or compensation can be used to minimise the effectof vibrations as for example shown in International Application No.PCT/AU97/00005, this results in an increase in the delay between thebreaking of the light beam and the subsequent actuation of the safetysystem to stop the press. Such delays should preferably be minimised asfar as possible, and preferably eliminated.

It is therefore an object of the present invention to provide a safetysystem for an industrial press that overcomes at least one of thedisadvantages associated with the prior art.

With this in mind, the present invention provides a safety system for anindustrial press having a moveable section, the safety means including:

-   a laser emitting means for emitting a continuous planar laser beam    having a generally constant lateral width;-   a light receiving means for receiving the laser beam and for    detecting when an object intersects the laser beam; and-   a control means for stopping or preventing movement of the moveable    section of the press when the receiving means detects that the laser    beam has intersected an object.

The use of a continuous planar laser beam having a generally constantlateral width means that the laser beam can cover a relatively wide areawhen compared with a conventional laser beam while at the same timeensuring that there are no “spaces” through which an object can passwithout detection.

The industrial press can for example be a press brake having a blade andan anvil moveable relative to each other. The laser beam may be emittedimmediately adjacent the leading edge of the blade. According to onepreferred embodiment of the present invention, the plane of the laserbeam may be horizontal and located between the blade and anvil of thepress brake. Furthermore, the laser emitting means and the lightreceiving means may be mountable on the blade, and may move with theblade it that part is the moveable section of the press brake. Thisensures that the introduction of an object close enough to the blade tointersect the laser beam will stop or prevent the operation of thepress. Alternative orientations of the laser beam are however alsoenvisaged. For example, the laser beam can be emitted in front of theblade with the plane of the laser beam being generally vertical.Alternatively, the safety system may emit a plurality of planar laserbeams. For example, laser beams can be emitted both in front of andunder the cutting blade. This provides an “L” shaped configuration ofplanar laser beams.

The laser emitting means may include a laser emitter, for example alaser diode for emitting a laser beam, and a lens assembly for varyingthe configuration of the laser beam emitted from the laser diode. Laserbeams emitted by such laser emitters are typically circular in crosssection. The lens assembly converts this laser beam into a laser beam ofgenerally planar shape and having a generally constant lateral width. Itshould be noted that some dispersion of the laser beam may occur thefurther away a point on the laser beam is from the laser emitter. Thisdispersion is however relatively insignificant within the range ofdistances that the laser beam must be emitted over, typically between 2to 12 meters.

The lens assembly may include a cylindrical prism for initiallyexpanding the laser beam into a laser beam having a planar fan shapedconfiguration. The lens assembly may also include a converging lens forrefocussing the fan shaped laser beam to a planar laser beam having agenerally constant lateral width. The original laser beam emitted fromthe laser emitter has virtually parallel “lines of light”. The lightintensity when measured across the lateral width of the planar laserbeam can however vary. This is due to the refractive effect of the lenson the laser beam which can cause a deflection in the lines of lightwithin the laser beam resulting in an overlapping of the lines of lighttherein. The “shadow” produced by an object intersecting the laser beammay therefore not be detected by the receiving means as the lines oflight passing the object can overlap thereby obscuring any shadowproduced by the object. A correcting lens may therefore need be providedafter the converging lens to straighten the lines of light of the laserbeam refocussed through the converging lens. This correcting lens mayfor example be in the form of a lenticular lens having a plurality oflens sections which respectively straighten the portion of the laserbeam passing therethrough. Alternatively, a series of separate parallellenses may be placed side to side in front of the converging lenses,each lens correcting a portion of the laser beam. This will ensure thatthe lines of light of the laser beam are generally parallel, and that anobject intersecting the corrected laser beam will cast a clear shadow anthe receiving means. According to another preferred arrangement, thelines of light of the laser beam may be straightened by a series ofcorrecting lenses located one after each other. For example, the lensseries may include a combination of a convex and concave lens located inseries. This lens series may be used in place of or together with thelenticular lens. Additional lenses may be provided depending on therequired accuracy of the correction of the planar laser beam.

The light receiving means may include a plurality of electronic lightreceivers aligned on along a common axis as a light receiver array. Thelight receiver array may be located at one end of a receiver body. Eachlight receiver may be located at the end of a light receiving passageprovided through the receiver body to prevent other light, eg. reflectedlight, from effecting the reading obtained from the light receiver.These light receiving passages may be configured to only see lightemitted by the laser beam. The light receiving passage may be in theform of a cylindrical bore provided within a solid block providing thereceiver body, the bore extending most of the way or completely throughthe block A plurality of said light receiving passages may be aligned ina parallel relation through the solid block. The light receivers may beprovided at the and of each passage, the opposing end of the passagesbeing exposed to and aligned with the lateral extent of the planar laserbeam.

Alternatively, the light receiving means may include a focussingarrangement, for example a “cylindrical” lens in front of the lightreceivers. Each light receiver may be located at the end of a lightreceiving passage. The passage may be provided by a box shaped enclosureseparated into separate parallel passages by dividing walls. Thecylindrical lens may be an elongate lens having a relatively uniformcross-section along its length. One side of the lens may have a constantradius of curvature, while the other side of the lens may be generallyflat. Such a lens focuses in one plane only and has a fixed focal point.It is however also envisaged that a plurality of lenses may be providedin from of the light receivers. The above described arrangement helps toensure that the laser beam is focussed on to the light receivers, evenwhere there is some displacement of the laser beams.

It has been found in practice that it is also possible to eliminate theneed for any separators in the enclosure for separating the planar laserbeam. The enclosure may therefore be completely hollow except for thelight receiver array at one end of the enclosure, and the cylindricallens on the other side thereof. This is because as long as the planarlaser beam enters the enclosure parallel to the sides of the enclosure,then all of the light receivers will be receiving light. If the planarlaser beam however enters at an angle to the sides of the enclosure,then a “shadow will be cast on at least one of the end light receiversof the light array thereby stopping the operation of the press.

All the light receivers may be aligned with and exposed to the samecontinuous planar laser beam during operation of the safety systemaccording to the present invention. Therefore any vibration of the presswhich results in lateral deflection of the laser beam within apredetermined range should not effect the operation of the receivingmeans. This is because all the light receivers may still be exposed tothe same laser beam even when there is a lateral deflection of the laserbeam as the width of the laser beam may be wider than the width of thelight receiver array. The safety system according to the presentinvention can therefore be relatively insensitive to vibration of thepress where the vibrations primarily result in lateral deflection of thelaser beam.

As it can therefore be possible to avoid the need for any softwarecompensation for the vibration effect on the laser beam, and anyintersection by an object of the laser beam can result in a directsignal being provided to the control means to stop or prevent movementof the press thereby eliminating or minimising any delay from thebreaking of the laser beam to the stopping of the press. The controlmeans can be in the form of an electronic control unit which receivessignals from the light receivers and controls the operation of thepress.

To improve the operational control of the safety system, the lightreceivers may be grouped into separate sections. Each section of lightreceivers may provide their own separate control signal. The lightreceivers can, for example, be grouped into a front section, a midsection and a rear section.

Both the laser emitting means and the light receiving means may berespectively mounted on supports on opposing sides of the moveablesection of the press. The supports may be respectively adjustable toallow the alignment and position of the laser emitting means to beadjusted. For example, where the moveable section is a bending orcutting blade, blades of different heights can be used, and the positionof the laser emitting means and light receiving means will need to beadjusted. Alternatively, only the laser emitting means need be adjusted,the light receiving means remaining fixed. This is, for example,possible where the light receiving means includes a said focussingarrangement in front of the light receivers.

It will be convenient to further describe the invention by reference tothe accompanying drawings which illustrate a preferred embodiment of thepresent invention. Other embodiments of the invention are possible, andconsequently the particularity of the accompanying drawings is not to beunderstood as superseding the generality of the proceeding descriptionof the invention.

IN THE DRAWINGS

FIG. 1 is a schematic view of a laser diode and lenses assemblyaccording to the present invention;

FIG. 2 is a cross-sectional view of a continuous planar laser beamemitted by the safety system taken along line A—A in FIG. 1 prior tocorrection according to the present invention;

FIG. 3 is a plan view of the continuous planar laser beam emitted by thesafety system prior to correction according to the present invention;

FIG. 4 is a plan view of a first preferred embodiment of the lightreceiving means according to the present invention;

FIG. 5 is an end view of the light receiver assembly of FIG. 4;

FIG. 6 is a side view of a second preferred embodiment of the lightreceiving means according to the present invention:

FIG. 7 is a perspective view of the cylindrical lens of FIG. 7.

FIG. 8 is a cross-sectional detail view of an industrial press showingthe location of the laser beam; and

FIG. 9 a is a schematic view of the safety system mounted on anindustrial press.

FIG. 9 b is a schematic view of the safety system in a furtherembodiment mounted on an industrial press.

Referring initially to FIG. 1, the industrial press safety systemaccording to the present invention includes a laser emitting means 1having a laser emitter 2, for example a laser diode, and a lensesassembly B for converting the laser beam 3 emitted from the laseremitter 2 into a continuous planar laser beam 9.

FIG. 2 is a cross section of the continuous laser beam 9 emitted by thelaser emitting means 1 taken along line A—A of FIG. 1 prior tocorrection. This laser beam 9 has a generally constant lateral width Walong its' elongate extent. Furthermore, the continuous planar laserbeam 9 has a generally constant thickness T. According to one possibleconfiguration of the present invention, the laser beam 9 can have alateral width of about 50 mm on average and a thickness of 3 mm onaverage. The angle of dispersion of the laser beam 9 is preferably equalto or less than 0.1%. It should be appreciated that alternativeconfigurations are possible in dependence on the application of thesafety system.

Returning to FIG. 1, the lens assembly 8 includes a cylindrical prism 5for initially expanding the laser beam 3 into a planar fan shaped beam6. This planar fan shaped beam 6 then passes through a converging lens 7for refocusing the fan shaped beam 6 into the planar laser beam 9 havinga generally constant lateral width. It has been found that the rightintensity when measured across the lateral width of the planar laserbeam 9 will vary across that lateral width. This variation of lightintensity is not normally visible to the eye. FIG. 2 neverthelessschematically shows the light intensity variation, with areas 10 ofincreased light intensity distributed across the lateral extend of thelast beam 9. It is considered that this is due to the refractive effectof the lenses 5, 7 which causes the parallel “lines of light” of theinitial laser beam 3 to be deflected such that they are no longerparallel in the planar laser beam 9 emitted from the converging lens 7.A correcting lens 11 is therefore placed in front of the converging lens7 to straighten the lines of light of the laser beam 9 so that they aregenerally parallel. The correcting lens 11 can be in the form of alenticular lens having a plurality of lens sections which respectivelystraighten the portion of the laser beam passing through that section.It is however also envisaged that a plurality of parallel lenses may beplaced side by side in front of the converging lens 7, each lenscorrecting a respective portion of the laser beam 9. The correcting lens11 could alternatively be replaced by a lens series 17 including aconcave lens 11 and convex lens 19 located one after each other andshown in dotted outline in FIG. 1. It is also envisaged that the lensseries 17 could be used in conjunction with the lenticular lens 11.Furthermore, additional correcting lenses could be added depending onthe accuracy of the focusing required.

FIG. 3 helps to illustrate better the effect of not correcting the linesof light schematically shown as lines 15 in FIG. 3. Where the planarlaser beam 9 is left uncorrected from the converging lens 7, thisresults in an “overlapping” of the lines of light 15. By comparison, inthe initial laser beam 3 from the laser emitter 2, the lines of lightwould be parallel, a typical characteristic of laser beam 5. Therefore,when an object intersects the planar laser beam 9, the overlapping ofthe lines of light 15 obliterates any shadow cast by the object 20.Therefore, the receiving means 22 will not detect any significant changein the light intensity of the planar laser beam 9 received by the lightreceiving means 22. The deflection of the lines of light is typicallyless than 0.1°. Nevertheless, because of the long transmissiondistances, the non-parallel nature of the uncorrected planar laser beam9 will have a significant effect on the operation of the safety system.

FIG. 4 shows in detail the construction of the light receiving means 22.This light receiving means 22 includes a plurality of electronic lightreceivers 26 aligned along a straight line. To eliminate the effect oflight other than that received from the planar laser beam 9, each lightreceiver 26 is placed at the end of an elongate cylindrical passage 24provided within a solid block 23. The light receiving means 22 furtherincludes a base plate 27 for supporting the light receivers 26 and afront transparent cover 25 for covering the inlet opening of thecylindrical passages 24.

FIG. 5 is an end view of the light receiving means 22 showing thealigned cylindrical passages 24 covered by the transparent cover 25. Theplanar laser beam 9 is simultaneously received by all of the lightreceivers 26, the area of the laser beam shining on the light receivingmeans 22 being shown in dotted lines 30. It can be seen that any lateralmovement of the laser beam 9 due to vibration of the industrial presswill not normally effect the operation of the safety system, with thelaser beam 9 still being received by all of the light receivers 26unless it is bent more than the distance X as shown in FIG. 5. Most ofthe vibration within industrial presses such as a press brake result, inside to side motion. Therefore, the effect of vibrating on the laserbeam 9 is minimised by aligning the plane of the laser beam 9horizontally. It is therefore generally not necessary to provide anysoftware correction for the signals produced by the light receivers 26due to the effect of vibration on the laser beam 9.

An alternative preferred embodiment of the light receiving means 22 ofpresent invention is shown in FIG. 6. Features which correspond to thearrangement shown in FIGS. 4 and 5 are designated with the samereference numeral. The light receivers 26 are located in the rear of anenclosure 38 and a “cylindrical” lens 37 is located in front of thelight receivers 26 and extending in front of all the light receivers 26.The cylindrical lens 6, which is shown in perspective in FIG. 7 has aforward side 39 with a constant radius of curvature. The rear side 40 ofthe lens 37 is generally flat. The cross-section of the lens 37 isgenerally constant along its length. In practice, the lens 37 is locatedin front of all the light receivers 26 so that the curve of the forwardside of the lens 37 is running in a vertical plane. Such a lens 37 istypically about 50 mm in height. A series of parallel and generallyvertical dividing walls 35 are provided with the enclosure 38 toseparate the enclosure 38 into a series of parallel light receivingpassages 24, with a light receiver 28 being provided at the end of eachpassage 24. It is however also possible to use a hollow enclosure 38without any partitions as previously discussed.

Having such a cylindrical lens 37 ensures that whenever the laser beam 9hits the lens 37 in the vertical plane, the light is focussed back tothe light receivers 25 in that one plane. In other words, the lens 37focuses light in one plane only. Such lens 37 also have a fixed focalpoint. This arrangement also ensures that the laser beam 9 will only bedirected to the light receivers 26 if the beam 9 is horizontal (ieperpendicular) to the lens 37. The lens may allow a tolerance from thehorizontal plane of typically about 1°, although this tolerance may beadjusted. This means that the light receivers 26 will only accept thelaser beam 9 if it is running parallel to the component of the pressbeing controlled, for example a movable blade 30 as shown in FIG. 6. Thedividing walls 36 within the enclosure 38 act to ensure that the lightis coming straight to the light receivers 26 within said tolerance inthis horizontal plane.

It is, however, also envisaged that a plurality of separate lenses beprovided in front of the high receivers 26, with each lens focussing arespective section of the light beams. In this arrangement, the lensescould be of the more conventional circular type.

FIG. 6 shows in dotted lines other positions of the leading edge of theblade 30 where different blades 30 are used. The laser beam 9 musttherefore be repositioned for each different blade 30 as shown in FIG.6. The use of such a cylindrical lens 37 therefore allows the laser beam9 to be at different heights due to differences in the depth of theblade 30 while still allowing the laser beam 9 to be focussed to thelight receivers 2G.

The light receivers 26 are positioned close together to thereby allowthe laser beam 9 to be received across the width of the field of thatlaser beam 9. These light receivers 26 can be grouped to receivedifferent segments of the beam 9, eg front section, mid section and rearsection. This is so that, if required, an intersection of the laser beam9 in different sections of the laser beam 9 can be responded to indifferent ways. For example, the intersection of the front section canresult in the stopping and “jump back” of the movable blade 30.Intersection of the mid section of the laser beam 9 is used to trigger a“mute point” setting as well as provide a stop and jump back response ofthe blade 30. The mute point is the point beyond which the blade 30 willtravel even if there is an intersection of the laser beam 9. Normallythe laser beam 9 is triggered a short distance (typically approximately4 mm) before it reaches the surface of the material to be bent and muted(ie. desensitized) to allow the bending process. It is considered that,at this distance, the smallest obstruction (ie a finger) could not bepresent. Finally, intersection of the rear section of the laser beam 9will stop the blade 30, but without any jump back thereof. Also whenswitched into a special mode of operation, this rear section can bemuted a few millimeters further away from the material being bent.Therefore, if a back gauge 50, a standard apparatus on many pressbrakes, is brought in close to the blade 30 to do very short bends sothat it is close enough to intrude onto the rear section of the laserbeam 9, the back gauge 50 will not interrupt the bending process (seeFIG. 8). This muting of the rear section of the laser beam 9 early, isconsidered safe because:

-   1. The roar of the press is far less likely to be accessed by the    operators (and assistants) in normal working conditions; and-   2. To help compensate (in this special mode only) the blade 30 stops    at the mute point and needs a further foot switch application for    the closing operation. This also ensures the operator knows he is in    this special mode.

The safety system according to the present invention may also provideother responses, for example, when the press is required to manufacturea box or tray where the sides thereof may be upstanding and maytherefore intersect the laser beam 9 as the blade comes down. Thereforeat a tray model of operation, when laser beam front section only isinterrupted the first time, the blade 30 stops. If at least one of theother sections of the laser beam 9 are clear, then the safety systemallows a closing movement of the blade 30 after foot switch operatedunder this tray mode. This is to allow the sides of a tray or box tointerrupt the front section of the laser beam 9 while still allowing theblade 30 to continue to move. The rear section of the laser beam 9 mayalso need to be “muted” to allow the end wall of the tray to be formed.Therefore, the blade 30 will initially stop when the rear section isintercepted, but will continue following the pressing of the foot switchif the centre section is still clear. This mode always gives fullprotection of the full width of the laser beam 9 down to the upstand onthe tray or box and, after a stop, only allows downward movement if theportion of the laser beam 9 directly under the blade 30 is still clearensuring that fingers are not left under the blade in the final closingmovement.

FIG. 8 is a schematic cross sectional view showing the position of theplaner laser beam 9 relative to the blade 30 and anvil 35 of a pressbrake. The planar laser beam 9 is located closely adjacent to theleading edge 32 of the blade 30, the plane of the laser beam 9 beinggenerally horizontal. The laser emitting means 1 and light receivingmeans 22 can be mounted on the blade 30 (see FIG. 9 a) or on the supportstructure (not shown) for the blade 30. Therefore, where the press brakeis of the type having a movable blade 30, the safety system will movetogether with the blade 30. Also shown is the movable back gauge 50previously referred to.

FIG. 9 a shows the laser emitting means 1 and light receiving means 22supported on brackets 45, 46, on the blade 30 of a press brake. This isapplicable for both upstroking and downstroking press brakes.

The laser beam 9 is typically set at a distance in the press of 8 mmbetween the leading edge of the blade 30 and the centre line of thelight beam 9. There is some tolerance allowed but essentially thisdistance must be equal to or greater than the stopping distance of theblade 30 after it has a stop signal.

The emitting means 1 and light receiving means 22 can be mounted onadjustable brackets 45, 46, so they can be accurately adjusted to thisdistance whenever the blade 30 is changed for different bendingprocesses. (The vertical depth of these blades 30 can often vary.) Theadjusting brackets 45, 46, are refined to make these adjustmentsrelatively easy but due to the accuracy needed with laser beams 9, itdoes need some work by the operator to get both ends aligned properly.

The press will never operate until both ends are aligned and the lightreceiving means 22 is receiving from the laser emitting means 1.

The use of the cylindrical lens 37 is the light receiving means 22allows it to be set at a height that can accommodate the shortest blade30 and it will accept any blade, for example up to 50 mm deeper.

As shown in FIG. 9 b, this means that the light receiving means 60 canstay fixed 65 (only adjusted if the blade has an excessive depth) andthe light emitting means 1 is adjusted vertically to suit the blade 30.Because of this overall design, the adjusting for varying blades andalignment of either the emitter end or of both ends is very easy in thisvertical plane. Thus also helps with any vibration. Vibration of thesystem, and the necessary alignment issues, as raised on page 6 line 12,may be accommodated. The adjusted width as shown in FIG. 5 permits adirect signal to be provided to the control means 55 and so minimizingany delay caused by unnecessary breaking of the press.

1. A safety system for an industrial press having a moveable section,the safety system comprising: a laser emitting means for emitting acontinuous planar laser beam having a generally constant lateral width;a light receiving means for receiving the laser beam and for detectingwhen an object intersects the laser beam; and a control means forstopping or preventing a movement of the moveable section of the presswhen the receiving means detects that the laser beam has intersected anobject.
 2. A safety system according to claim 1, wherein the industrialpress has a blade and an anvil moveable relative to each other, thesafety system being locatable such that the planar laser beam is emittedimmediately adjacent the leading edge of the blade.
 3. A safety systemaccording to claim 2, wherein the plane of the planar laser beam is atleast substantially horizontal and is locatable between the blade andanvil of the press brake.
 4. A safety system according to claim 2,wherein the plane of the planar laser beam is at least substantiallyvertical and is locatable in front of the blade.
 5. A safety systemaccording to claim 2, wherein the laser emitting means and the lightreceiving means is mountable on or immediately adjacent the blade, andis movable with the blade when it is the moveable section of the press.6. A safety system according to claim 1, further comprising a pluralityof laser emitting means and associated said light receiving means foremitting a plurality of said planar laser beams.
 7. A safety systemaccording to claim 1, wherein the laser emitting means includes a laseremitter for emitting a laser beam, and a lens assembly for varying theconfiguration of the laser beam into a said planar laser beam ofgenerally planar shape and having a generally constant lateral width. 8.A safety system according to claim 7, wherein the lens assembly includesa cylindrical prism for initially expanding the laser beam into a laserbeam having a planar fan shaped configuration, and a converging lens forrefocusing the fan shaped laser beam to a planar laser beam having agenerally constant lateral width.
 9. A safety system according to claim8, wherein the lens assembly further includes at least one correctinglens provided after the converging lens for straightening the lines oflight of the planar laser beam.
 10. A safety system according to claim9, wherein the correcting lens includes a lenticular lens formed fromone or more lens sections.
 11. A safety system according to claim 9,wherein the correcting lens includes a lens series having at least oneconvex and at least one concave lens.
 12. A safety system according toclaim 7, wherein the light receiving means includes a receiver body, anda plurality of light receivers aligned along a common axis as a lightreceiver array and located at one end of the receiver body, wherein eachlight receiver is located at one end of a respective light receivingpassage provided through the receiver body.
 13. A safety systemaccording to claim 7, wherein the light receiving means includes areceiver body, a plurality of light receivers aligned along a commonaxis as a light receiver array and located at one end of the receiverbody, and a lens provided at the opposing end of the receiver body forfocusing the planar laser beam onto the light receivers.
 14. A safetysystem according to claim 13 wherein the lens is a cylindrical lens, thelens focusing the planar laser beam onto the light receivers even whenthe planar laser beam is displaced laterally from a plane extendingthrough the light receivers.
 15. A safety system according to claim 14,wherein the receiver body is an enclosure separated into separateparallel passages by dividing walls.
 16. A safety system according toclaim 12, wherein the width of the planar laser beam is wider than thelength of the light receiver array.
 17. A safety system according toclaim 12, further including an electronic control unit for receivingcontrol signals from the light receivers and for controlling theoperation of the press, wherein the press is stopped when the receipt ofthe light of the planar laser beam to at least one of the lightreceivers is blocked due to a breaking of the planar laser beam.
 18. Asafety system according to claim 17, wherein the light receivers aregrouped into a separate sections, with each section of light receiversproviding a separate control signal to the electronic control unit. 19.A safety system according to claim 1, wherein both the laser emittingmeans and the light receiving means are respectively mounted on supportson opposing sides of the moveable section of the press, wherein at leastone of the supports is adjustable to allow the alignment and position ofat least one of the laser emitting means or the light receiving means tobe adjusted.
 20. A safety system according to claim 1, wherein the laseremitting means is mounted on a support on one side of the moveablesection of the press, such that the support is adjustable to allow thealignment and position of the laser emitting means whilst the laserreceiving means remains in a fixed position.
 21. A safety systemaccording to claim 1, wherein the angle of dispersion of the planarlaser beam is equal to or less than 0.1 degrees.
 22. A safety system foran industrial press having a moveable section, the safety systemcomprising: a laser that emits a continuous planar laser beam having agenerally constant lateral width; a light receiver, aligned with thelaser, that receives the laser beam and detects when an objectintersects the laser beam; and a control, in electronic communicationwith the light receiver, that is capable of stopping or preventing amovement of the moveable section of the press when the light receiverdetects that the laser beam has intersected an object.